2002 Ford Escape 3.0 Misfire - ignition coils connected wrong

This vehicle came in with a long history, a severe misfire complaint that two shops couldn’t fix, and lots of parts changing along the way. Testing and careful analysis led to a surprising fix. All of the testing methods shown can be applied to any vehicle with a coil-on-plug ignition system.

2004 Mazda MPV Low Power Case Study:

Ignition testing with a scope (Secondary Waveforms) - open plug wire:

Secondary Ignition Waveforms (common faults):

How to determine which cylinder is misfiring (cylinder drop test):

How to check for a jumped timing chain or belt:

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For more information on this topic, I have written a “field manual” called Engine Performance Diagnostics which is available as an eBook or paper book.

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On ScannerDanner Premium I will bring you right into my classroom at Rosedale Technical College. You will find page for page lectures taken right from my book as well as exclusive classroom type case studies. What is so special about these classroom case studies? I pull live problem vehicles directly into my classroom and we troubleshoot them in real time, using and applying the theory and testing procedures we learn during the classroom lectures. There is no better on-line training of how to troubleshoot automotive electrical and electronics systems anywhere!